Heating System

OPERATION

NOTE: The Blower Circuit is the same for both the Heater and A/C-Heater System.

Main Heater
With the Ignition Switch in "ACC" or "RUN" and the Heater Control Assembly in any position except "OFF", battery voltage is applied to the dash-mounted Blower Motor. The blower Motor Switch applies ground to the Blower motor through the Blower Motor Resistor Assembly. The Blower Motor Resistor Assembly is a resistance network that controls Blower Motor speed by controlling current to the motor.

Auxiliary Heaters
The Blower circuit for the Auxiliary Heater System uses two Blower Switches (to select blower speed): the Front Auxiliary Blower Motor Switch and the Rear Auxiliary Blower Motor Switch. The Front Auxiliary Blower Motor Switch, part of the Main Front Control Assembly, has an "OFF" position, three speed positions and a REAR position. With the Front Auxiliary Blower Motor Switch in the "REAR" position, ground path to the Rear Auxiliary Blower Motor Switch is completed. This allows rear seat control of the Auxiliary Blower Motor.

When the Switch is moved to the "REAR" position, the Auxiliary Blower Motor is controlled by the Rear Auxiliary Blower Motor Switch, located in the auxiliary unit. The Rear Auxiliary Blower Motor Switch has an "OFF" position and four speed positions. Both the Front and Rear Auxiliary Blower Switches operate similarly to the Main Blower Switch.